<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
	<title>Insert title here</title>
	<style type="text/css">
		#d1{
			width:100px;
			height:100px;
			/*border:1px solid red;*/
			border-bottom: 1px solid red;
			
		}
	</style>
	</head>
	<body>
		<div id="d1">div1</div>
	</body>
</html>